Adaptive Finite-Time Control for Attitude Tracking of Rigid Spacecraft

This paper investigates the attitude tracking control problem for rigid spacecraft with inertia uncertainties and external perturbations. Spacecraft attitude dynamics and kinematics are initially converted into Lagrange-like model and formulated as a state-space form described by the modified Rodrigues parameters (MRPs). Robust controllers contain two parts and use geometric homogeneity, integral sliding mode (ISM) technique, and adaptive laws. One part proposes a class of feedback controllers to accomplish finite-time stabilization of the second order dynamics without the lumped uncertainties. The other part rejects bounded uncertainties based on ISM associated with adaptive laws. Moreover, a rigorous proof of finite-time convergence is developed. The proposed control laws provide finite-time convergence, robustness, and faster and higher control precision, and these algorithms require no information about inertia uncertainties and external disturbances, which cannot be obtained in practical systems. Finally, numerical simulations are also carried out to illustrate the effectiveness of these methodologies.